Bug 1794956 - TransferToImageBitmap should reset bitmap but not state. r=gfx-reviewers,lsalzman

s/Reset/ResetBitmap/ and implement for WebGL and WebGPU.

Differential Revision: https://phabricator.services.mozilla.com/D159346

dom/canvas/ClientWebGLContext.h

@@ -962,10 +962,7 @@ class ClientWebGLContext final : public nsICanvasRenderingContextInternal,
     return NS_ERROR_NOT_IMPLEMENTED;
   }
 
-  NS_IMETHOD Reset() override {
-    /* (InitializeWithSurface) */
-    return NS_ERROR_NOT_IMPLEMENTED;
-  }
+  void ResetBitmap() override;
 
   UniquePtr<uint8_t[]> GetImageBuffer(int32_t* out_format) override;
   NS_IMETHOD GetInputStream(const char* mimeType,